High pressure fuel injection apparatus for internal combustion engines



June 29, 1965 URATARO ASAKA ETAL 3,191,312

HIGH PRESSURE FUEL INJECTION APPARATUS FOR INTERNAL COMBUSTION ENGINES Filed 00";- 12, 1964 ATTORNEYS United States Patent 3,191,812 r HIGH PRESSURE FUEL INJECTION APPARATUS FOR INTERNAL COh/EUSTIGN ENGWES Urataro Asalra and Kiyoshi Osalri, Saitama-lren, Japan, assignors to Kabushilri Kaisha Honda Gijutsu Kenky: usho, Saitama-ken, Japan, a corporation of Japan Filed Oct. 12, 1964, Ser. No. 403,249 Claims priority, application Japan, Feb. 25, 1964, 39/ 9,357 3 Claims. (Cl. 222-250) The present invention relates to improvements in highpressure fuel injection apparatus for internal combustion engines.

According to one feature of the present invention, there is provided an improved fuel injection apparatus characterized in that on opposite ends of a free piston Within a main cylinder, there are provided by hollowing out to cooperate therewith a pair of subsidiary piston cylinders which are smaller in diameter than the main cylinder and each subsidiary cylinder has its own subsidiary piston, and the subsidiary cylinders are in communication with injection nozzles of an internal combustion engine, and each subsidiary piston and subsidiary cylinder is provided on the lateral surface of the axially middle portion thereof with a valve port for communicatingbetween the subsidiary cylinder and the interior of the main cylinder. Thus in accordance with the right and left movements of the free main piston caused by the compressed oil supplied alternately to right and left chambers of the main cylinder, at the ends of the main piston through a distributing valve from an oil pump, the cycle is repeated alternately that each subsidiary piston is in turn supplied with compressed oil through its valve opening and that the valve opening is then closed for further compressing the oil in the interior.

According to a second feature of the present invention, the relative positions between each subsidiary piston and the corresponding subsidiary cylinder, can be axially adjusted at will for controlling the oil injection volume.

According to a third feature of the present invention, an oil conduit leading from an oil distributing valve is divided between two distributing conduits which respectively terminate at a point at the end of the main cylinder, and at a position somewhat inside from the end of the main cylinder, respectively, of each respective end portion of the main cylinder, and the former conduit is provided with a check valve therein so that in accordance with movement of the free main piston towards the end surface of the main cylinder, the oil pressure between the two locations is sharply increased for effecting shock absorption.

One embodiment of the present invention will be described as an example with reference to the sole figure of the accompanying drawing.

Referring to the drawing, 1 denotes a main cylinder, 2 denotes a free main piston within the same, and 3, 3, denote a pair of chambers formed on opposite sides thereof within the cylinder. In the opposite end surfaces of the main piston 2, there are hollowed out cylindrical recesses to form subsidiary cylinders 5, 5, cooperating With stationary subsidiary pistons 4, 4, which are smaller in diameter than the main piston 2. Each subsidiary cylinder 5 is in communication through channels with a respective injection nozzle 8 of an internal combustion engine (not shown) through an axial bore 6 in the corresponding subsidiary piston 4 and a pipe channel 7 connecting through the wall of main cylinder 2 to the end of the axial bore 6, and the subsidiary cylinder 5 is also in communication with the corresponding chamber 3 at end of the main cylinder 1 through a radial valve port 9 leading from the axially middle portion of the axial ice bore 6 and being open at the lateral surface of the middle portion of the subsidiary piston 4.

Each subsidiary piston 4 is provided at its external end with a rack 10, and a pinion 11 is engaged therewith so that by properly rotating the pinion 11, the initial posi tion of the subsidiary piston 4 may be adjusted in its axial direction, whereupon, as will be described hereinafter, the closing time of the valve opening 9, and accordingly the injection amount, can be varied. In this adjusting operation, the two pinions 11, 11, are to be rotated together by suitable control symmetrically with one another for moving the right and left subsidiary pistons 4, 4, simultaneously and equally.

The main cylinder 1 is in communication at each end with a source of compressed oil such as an oil pressure pump 14 by a respective oil conduit 12 through a distributing valve 13 for alternately driving compressed oil into the chambers 3, 3. The distributing valve 13 may be of reciprocating type, but that shown on the drawing is of rotating type and is constructed as follows.

The distributing valve 13, as shown, comprises a stationary valve housing 15 of hollow cylindrical drum type, and its interior valve body 16 which is rotatably driven by an engine (not shown). The valve housing 15 has in its inner surface an annular oil inlet groove 17 always in communication with the pump side 14, and an annular oil discharging groove 18 always communicating with the pump air side, these grooves 17 and 18 being arranged as for right and left. The valve housing also has in the middle portion thereof a pair of valve ports 20, 20, positioned degrees apart from one another, and communicating by channels with the two chambers 3 and 3. The valve body 16 has in its axial direction a pair of guide holes 21 and 21, one long and one short, always in communication with the oil intake groove 17 and the oil discharging groove 19, respectively, and these guideholes 21, 21 have at the positions opposite to the valve openings 20, 20, a pair of valve openings 22, 22, positioned 180 degrees apart.

It, thus, the valve body 16 is rotated, the cycle is repeated alternately at every 180 degrees of rotation of the same, that one of the two chambers 3, 3 is in communication with the pump side 14 of the valve, and the other chamber is in communication with the air side 18 of the valve, so that one is in communication with the air side 18 and the other is in communication with the pump side 14. The oil conduits 12, 12 communicating with each chamber 3 of the main cylinder 1, are respectively split to be connected simultaneously to two positions, that is, a main guide opening 23 at the position more or less displaced inwardly from the end surface of the chamber 3, and a subsidiary guide opening at the end surface position, and the latter conduit is provided with a check valve 25.

By this construction, as will be described hereinafter, after the moment when the main guide opening 23 is closed by the free main piston 2 having moved in one direction, and closing the first opening, the oil at that portion will be compressed to increase sharply its pressure for effecting shock absorbing action for the free main piston.

Referring further to the sole figure of the drawing, 26 denotes a prime mover engine for driving the pump 14; 27 denotes a lubricating oil compressing pump for supplying lubricating oil for the sliding and rotating portions of the main cylinder 1 and the distributing valve 13; 28 denotes a prime mover engine for driving the same.

29 denotes on orifice connected to chamber 3 for removing bubbles, and through the orifice the bubbles within the working oil may be exhausted to the exterior. 30 denotes a check valve interposed in the pipe channel 7 con- 3 necting between the interior of the subsidiary piston 4 and the injection nozzle 8.

The operation of the apparatus is as follows:

, Consideran instant when, as is shown on the drawing,

the compressed oil from the pump 14 is driven through a respective oil conduit 12 on'the right into the right side chamber 3 of the main cylinder 1, and at the same time part of the compressed oil is driven through the valve opening 9 to the subsidiary cylinder 5 on the right, whereby the free main piston 2 is moved to the left by having applied over its whole'right side suriace tl e compressed oil.

If, due to this condition, the respective left side oil conduit 12 becomes in communication with the pump 14 by action of the distributing valve 13, the oil compressed by the pump 14 is driven first through the subsidiary guide opening 24 and then later through the main guide opening 23 into the left side chamber 3 of the main cylinder 1, to move the free main piston 2 rightwardly. In accordance with this movement of the free main piston 2, the valve opening 9 is then opened so that through this opening the compressed oil is, supplied also to the subsidiary cylinder 5. As a result thereof, the free piston 2 is applied over its whole left surface with compressed oil to move it rightwardly. In this case, the compressed oil previously driven into the right side subsidiary cylinder 5 is subjected to high compression by the rightward movement of the main piston 2 following the closing of the valve opening 9 by a slight rightward movement of the free main piston 2, whereby the oil attains to a high pressure for being injected from the injection nozzle 8.

That is, the free main piston 2 receives compressed oil force over the entire surface on it's'left side, and the right side subsidiary cylinder 5 is so small in size in comparison therewith that the force is doubled to bring about high pressure. At the next operation of the distributing valve 13, high pressure is produced within the left-hand side subsidiary cylinder 5. Thereafter, this cycle is repeated alternately. If, in this case, the initial position of the subsidiary piston 4 is axially adjusted by rack 10 and pinion 11, the position of the valve opening 91, and accordingly, the closing time of the valve opening 9 is adjusted for varying the injection amount from the injection nozzle at every operation. Furthermore, after the main guide opening 23 has been closed as the free main piston 2 approaches the end surface at each end, the oil pressure between the two is rapidly increased for alleviating the shock between the two.

According to the present invention, as has been described, the cycle is repeated alternately that by the pressure oil acting on the large facial surface of the free main piston, the opposite side subsidiary piston cylinder of comparatively small diameter is operated, so that high pressure may be obtained easily and at high efficiency, and there is no difficulty because the supply of compressed oil to the subsidiary piston is performed automatically. Further, the injection volume may be adjusted by adjusting the initial axial direction position of the subsidiary piston, and this can be easily performed to alleviate the shock at each end of the free piston.

In the embodiment shown in the drawing, each subsidiary piston cylinder has its own respective injection nozzle 8 connected thereto.

A modification, however, is possible in which the right and left subsidiary piston cyilnders have only one common injection nozzle connected thereto for both, though this modification is not illustrated in the drawing.

We claim:

ll. In a fuel injection apparatus, a main cylinder, a main piston freely slideable mounted in said main cylinder and having two opposite terminal faces, a pair of subsidiary cylinders respectively excised in the two terminal faces of said main piston, said subsidiary cylinders being of substantially smaller diameter than said main cylinder, a pair of subsidiary pistons mounted for displacement within said subsidiary cylinders respectively, each said subsidiary piston respectively being provided on a lateral face thereof with a valve opening, said main cylinder having two separate chambers formed therein, supply means for alternately supplying oil under pressure to the two chambers of the main cylinder for causing alternately movements in opposite directions of said free main piston, whereby the delivery of oil through said valve opening cylically delivers oil under pressure to each said subsidiary piston for compressing the oil in each said subsidiary cylinder.

2. Apparatus according to claim 1, and adjusting means externally mounted adjacent each subsidiary pistion for axially adjusting the initial position of each said subsidiary piston with relation to its respective subsidiary cylinder.

3. Apparatus according to claim 1, said means for supplying oil under pressure to said chambers being provided with two delivery means axially substantially displaced on the external cylindrical peripheral surface of said main cylinder.

No references cited.

LOUiS I. DEMBO, Primary Examiner. 

1. IN A FUEL INJECTION APPARATUS, A MAIN CYLINDER, A MAIN PISTON FREELY SLIDEABLE MOUNTED IN SAID MAIN CYLINDER AND HAVING TWO OPPOSITE TERMINAL FACES, A PAIR OF SUBSIDIARY CYLINDERS RESPECTIVELY EXCISED IN THE TWO TERMINAL FACES OF SAID MAIN PISTON, SAID SUBSIDIARY CYLINDERS BEING OF SUBSTANTIALLY SMALLER DIAMETER THAN SAID MAIN CYLINDER, A PAIR OF SUBSIDIARY PISTONS MOUNTED FOR DISPLACEMENT WITHIN SAID SUBSIDIARY CYLINDERS RESPECTIVELY, EACH SAID SUBSIDIARY PISTON RESPECTIVELY BEING PROVIDED ON A LATERAL FACE THEREOF WITH A VALVE OPENING, SAID MAIN CYLINDER HAVING TWO SEPARATE CHAMBERS FORMED THEREIN, SUPPLY MEANS FOR ALTERNATELY SUPPLYING OIL UNDER PRESSURE TO THE TWO CHAMBERS OF THE MAIN CYLINDER FOR CAUSING ALTERNATELY MOVEMENTS IN OPPOSITE DIRECTIONS OF SAID FREE MAIN PISTON, WHEREBY THE DELIVERY OF OIL THROUGH SAID VALVE OPENING CYLICALLY DELIVERS OIL UNDER PRESSURE TO EACH SAID SUBSIDIARY PISTON FOR COMPRESSING THE OIL IN EACH SAID SUBSIDIARY CYLINDER. 